A goal of this study is to determine the contribution of intestinal cytochrome P450 3A to the observed first-pass metabolism of midazolam following oral administration using silmultaneous intravenous and oral administration of midazolam and a stable isotope (N-midazolam). A second goal of the study is to determine if clarithromycin inhibits the metabolism of midazolam following oral administration at the intestinal or hepatic level.